Spring Rate Suggestions for '68 Camaro

[Mkelcy]

I've finally got my '68 Camaro build on the street. It's got a 21st Century Street Machine subframe, a Lateral Dynamics 3 link rear, LS3 engine and T56 transmission. Because of the intrusion of the upper link into the rear seat area, I've elected to eliminate the back seat, so it will never carry more than two people. The car is Dynamatted but doesn't otherwise have weight added. The battery in in the trunk.

I've just gotten the car on the road. Although I've got very little seat time, my impression is that it's over sprung for my use, which is spirited local driving and long distance trips with little to no auto-cross or track time.

For the front I'm using 450 lb./in. springs, a 1.15" hollow sway bar that has a rate of 300lbs./5 degrees of twist and QA1 single adjustable coilover shocks dialed down to the softest setting. For the rear I'm using 200 lb./in. springs on AFCO double adjustable M2 coilover gas charged shocks with a remote reservoir, both compression and rebound dialed down to the softest settings and, having just checked, the former gas charge on the shocks has leaked away over the years, so they are not charged; no rear sway bar. As I said, I'm just starting to get miles on the car, so the shock settings are simply to get a baseline from which to make adjustments (and I'll throw a 50 lb./sq. in. nitrogen charge on them when I get my fill kit).

I'm thinking of stepping down to 400 lb./in. springs for the front and 175 lb./in. springs for the rear.

Anyone have any thoughts on whether that's enough of a step down (especially after I get a charge on the rear shocks) or too much; am I looking at the wrong part of the suspension (say the front sway bar, and/or adding bar for the rear if I go with softer springs); or should I get the rear shocks charged and get more seat time before doing anything?

Thoughts?

I'm looking for a little smoother ride while still allowing for excellent street handling.

[dhutton]

How much preload do you have on your coilovers? In my experience a lot of preload leads to a lousy ride on the street. The preload "fires off" when going over abrupt drops in the road which can make the ride seem harsh. I found a stiffer spring with less preload gave a better ride for me.

Just my two cents, not an expert by any means.

Don

[Mkelcy]

Originally Posted by dhutton

How much preload do you have on your coilovers? In my experience a lot of preload leads to a lousy ride on the street. The preload "fires off" when going over abrupt drops in the road which can make the ride seem harsh. I found a stiffer spring with less preload gave a better ride for me.

Just my two cents, not an expert by any means.

Don

At full extension, hardly any on the rear; I'll have to check the front, but my recollection is that I don't have much there, either. The car already rode a little high, and I didn't want to raise it more by preloading it a lot.

[dhutton]

I've got some 12" 175 pound springs if you want to try them. Just PM me your address and I can send them out this week.

Don

[Penny]

Post a pic, I am subscribing.

[Vegas69]

Twenty five pounds won't be noticeable in regards to ride. Those are light springs. I'd say it's shock valving or you need to buy a Cadillac.